The present invention relates to improved cultivars of annual pasture and forage legumes of the Medicago genus (annual medics).
The present inventors have had extensive experience and success in the breeding and development of cultivars of pasture legume, in particular cultivars of annuals of the Medicago genus. Some years ago, they recognised that a major impediment to adoption and use of Medicago cultivars was seed cost, and that a major component of that seed cost related to the difficulty of harvesting and cleaning the seed. This is because, at maturity, the seed pods are dropped from the plant, and harvesting of seed entails vacuum harvesting the pods off the ground. The harvesting process is therefore slow, and requires specialised and powerful equipment, with large fuel inputs.
Accordingly, the present inventors sought to develop a medic that does not drop its seed pods and therefore can be harvested cheaply and efficiently with conventional harvesting equipment. This pod holding characteristic has never been recorded in naturally occurring annual medics.
Pod shedding is a result of growth of a layer of cells across the pedicel (pod stalk) at the base of the pod, which cuts off nutrient flows into the maturing pod and leads to effective separation of the pod from the pedicel. At the slightest disturbance, the pod then drops to the ground under its own weight and, by the time the plant has itself matured, the pod has been shed. Research has indicated that control of development of this abscission layer of cells is genetically controlled.